1. Field of the Invention
The present invention relates to a photosensitive composition, a pattern forming material, and a photosensitive film, a pattern forming method, a pattern film, a low refractive index film, an optical device and a solid-state image device each using the same.
2. Description of the Related Art
A low refractive index film is formed, in an optical member, as an optical functional film contained in an antireflection film, a reflection film, a transflective film, a visible light-reflecting infrared-transmitting film, an infrared-reflecting visible light-transmitting film, a blue reflecting film, a green or red reflecting film, a bright line cut filter or a color correction film.
Not only in optical members having a flat surface profile but also in all of optical functional members such as luminance-enhancing lens film or diffusion film for liquid crystal backlight, Fresnel lens or lenticular lens used for video projection television screens, and microlens, the desired geometric-optical performance is obtained by designing the resin material to have a microscopic structure, and an optical functional film containing a low refractive index film is also required on the surface of such a microscopic structure.
In the case of using the low refractive index film as an antireflection film, a low refractive index film with a single-layer structure directly works as an antireflection film. As for the refractive index of an antireflection film having a single-layer structure, in the case where the base material is a transparent material such as resin material, a low refractive index of 1.2 to 1.35 is desired.
As the representative material for the low refractive index film, there are known a fluorine-based polymer material having a refractive index of 1.35 to 1.4, and a layer containing a porous material in which fine particles composed of a polymer of a fluorine monomer having a low refractive index of 1.37 to 1.46 are fused (see, for example, JP Patent No. 3718031), but a material having a refractive index of 1.3 or less is not obtained.
In addition to the above-described reflectance characteristics, it is demanded to solve various problems such as cumbersome production process. In JP-A-2010-31222 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and JP-A-2010-32996, a method of forming a pattern by using a silica-based material imparted with photosensitivity and exposing/developing the material itself is described as a patterning method using no photoresist so as to overcome the cumbersomeness of the production process, but the resolution in pattern formation is insufficient and at the same time, the low refractive index property of the obtained pattern is unsatisfied.